The popularity of energy drinks has increased dramatically since their introduction in the 1980s. These drinks now represent a $5 billion industry and are purchased primarily by male teenagers and young adults, especially those involved in sports. Recent advertising of these drinks has focused on women in an effort to grow the market. In addition to athletes, the drink is used by students to counteract daytime sleepiness consequent to too little sleep at night. A recent study found that 35 percent of teenagers regularly used energy drinks with 50 percent consuming one to four cans per month.

There are more than 200 brands of energy drinks. The primary ingredient in all of them is caffeine – lots of caffeine. A regular cup of brewed coffee contains somewhere between 80 and 120 mg caffeine and by law a cola beverage can not contain more than 65mg in a 12-ounce bottle.

Most energy drinks provide 154 to 280mg of caffeine with one brand containing 505mg in its 24-ounce container. There is no standard for the daily allowance of caffeine, but the American Dietetic Association recommends that children or women of reproductive age should not consume more than 300mg per day. Heavy use of caffeine frequently results in high blood pressure, palpitations, irregular heart beats, irritability, anxiety, mental confusion, tremors of the hands and limbs, thinning of the bones, nausea, insomnia and headaches. High caffeine consumption during pregnancy can be associated with premature birth, fetal growth retardation and decreased birth weight. Caffeine is a diuretic – it increases urine output. If athletes use caffeine as a stimulus before a game they can become dehydrated if they do not replace the fluid loss induced by caffeine.

A second ingredient in several energy drinks is Guarana. Since each gram of guaranine (the active ingredient) is converted into 40mg of caffeine the two agents have an additive effect. Most energy drinks have a high sugar content comparable to that found in sodas and fruit drinks. This is not unexpected since it has been shown that this, combined with caffeine, will improve both mental and physical performances. However, adolescents who consume these energy drinks in abundance are at risk for developing obesity or dental problems because of the sugar content.

The biggest concern with energy drinks, however, is that some contain alcohol often in a concentration similar to that in beer (4.2 - 5 percent) or even in wine (12 percent). In addition, it is not unusual for teenagers or young adults to add alcohol to energy drinks, especially those that contain fruit juices which mask the alcohol flavor. Thus persons imbibing these drinks may not be aware of the amount of alcohol they have consumed. In addition, teenagers who consume these drinks underestimate their degree of intoxication because of the amount of caffeine that they consumed in the drink. Despite their perceptions, the students’ motor coordination and visual reaction times were impaired when the students were tested. This can explain why students who reported consuming energy drinks with alcohol were twice as likely to ride in a car with an intoxicated driver.

This is not a hypothetical issue. A recent survey of 10 universities in North Carolina found that 25 percent of college students had consumed energy drinks mixed with alcohol in the last month. In 2010, 23 students from a college campus in New Jersey were hospitalized after becoming intoxicated due to drinking an energy drink mixed with alcohol. One month later nine university students in Washington State were hospitalized and one almost died after ingesting the same caffeinated alcoholic beverage. Both campuses have subsequently banned this beverage.

It is important that all parents, pediatricians and primary care physicians are aware of the side effects of ingesting high doses of caffeine especially when combined with alcohol. If you Google "energy drinks” you will find an abundance of facts about the topic.